Appeal from a decision of the Workmen’s Compensation Board, filed October 24, 1975. Claimant, a truck driver, suffered on-the-job injuries to his back in 1963, 1967 and on two separate occasions in 1970. On each of these occasions he was employed by a different employer. Subsequent to the fourth accident on September 21, 1970, a claim for compensation was filed. Appellants, the employer and carrier at the time of claimant’s injury on January 6, 1970, object to the award of compensation insofar as it apportions liability 50% to them and 50% to the employer and carrier at the time of the September 21, 1970 accident. Claimant’s right to compensation is not disputed. The record amply supports the conclusion that the incidents in 1963 and 1967 resulted in no extended lost time or disability and that claimant had recovered from them. On the basis of the testimony of Dr. Quinn, who performed surgery subsequent to the fourth incident, the board could properly find that only the two 1970 incidents contributed to claimant’s disability, and there is further medical evidence from which the board was entitled to conclude that each of these incidents contributed to the disability in equal proportions. The decision is therefore supported by substantial evidence and the findings of the board are sufficient to permit adequate judicial review. Decision affirmed, with costs to the Workmen’s Compensation Board. Koreman, P. J., Greenblott, Sweeney, Kane and Mahoney, JJ., concur.